Effects of aerated brackish water irrigation on growth of Lycium barbarum seedlings

The management of Lycium barbarum seedling has an important influence on its fruit yield and quality at mature stage. Pot experiments were conducted to investigate the effects of four water salinity levels (0.6 (fresh water), 1.5, 3.0 and 4.5 g/L) under non-aeration (O2 content of 8.5 mg/L) and aeration (15.0 mg/L) irrigation on soil enzyme activity and the physiological parameters and growth status of Lycium barbarum seedlings. The results showed that brackish water irrigation increased soil electrical conductivity by 1.8 - 5.8 times, inhibited soil enzyme activities by 12.1% - 52.0%, and decreased the net photosynthetic rate by 10.7% - 24.8%, transpiration rate by 24.3% - 27.3%, and plant water consumption by 0.9% - 18.0% compared with fresh water irrigation. Brackish water irrigation also significantly inhibited the growth of leaves, base stem, roots and biomass of Lycium barbarum seedlings. Compared with non-aeration irrigation, the micro-nano bubble aerated brackish water irrigation promoted the activities of urease and alkaline phosphatase by 0.5% - 33.0% and 4.4% - 9.0%, respectively, and increased net photosynthetic rate by 3.3% - 8.0%, plant transpiration rate by 0.1% - 25.3%, and water consumption by 0.7% - 5.0% under brackish water irrigation. It also promoted the growth of leaves, branches, base stem and roots, and increased the biomass accumulation of Lycium barbarum seedlings by 7.4% - 9.3%. The aerated water irrigation with micro-nano bubbles can alleviate the negative effects of salt stress on the growth of Lycium barbarum seedlings to varying degrees, so the salinity of irrigation water less than 3.0 g/L combining with the aerated disposal is suggested to be as an optional solution to the planting of Lycium barbarum seedlings in arid oasis regions.